E-cigarette companies promote their products as a healthier alternative to conventional cigarettes and even as a cessation aid.
But a new study by researchers at UC San Francisco found that cigarette users do not benefit from the added use of e-cigarettes, with no reduction in cigarettes smoked or health risks.
The study was published online July 25, 2018, in PLOS ONE.
While e-cigarettes deliver lower levels of nicotine compared to cigarettes, many smokers become dual users and maintain their cigarette habits.
“While some may view e-cigarettes as a means to quit or reduce smoking, instead these devices may simply add yet more toxic exposure on top of conventional cigarettes,” said senior author Gregory Marcus, MD, MAS, a UCSF Health cardiologist and director of clinical research in the UCSF Division of Cardiology.
In the PLOS ONE study, the researchers compared the self-reported smoking habits of 573 e-cigarette-only users, 1,693 cigarette-only users and 514 dual users. They also examined answers to survey questions regarding general health and breathing difficulty as well as 19 cardiopulmonary symptoms and conditions, such as chest pain, asthma and hypertension. The data is part of the broader Health eHeart Study, which included 39,747 overall participants from March 8, 2013, to March 1, 2017.
The researchers found that dual users actually reported smoking a median of one more cigarette per day compared to cigarette-only users (10 versus nine cigarettes). Moreover, among e-cigarette-only users and dual users, there were no significant differences in e-cigarette dose as measured by days of use in the past month, cartridges per day and puffs per day. In essence, this suggests that dual use does not reduce exposure to either cigarettes or e-cigarettes.
Nor does it reduce the health risks. Dual users reported lower general health and more breathing difficulty than cigarette-only users, as well as lower physical activity levels and higher depression and anxiety, Marcus said. Dual users were also more likely to have a history of arrhythmia (17.8 percent) compared to cigarette-only users (14.2 percent).
The researchers note that study participants who were previously heavy smokers may have been more likely to become dual users in an effort to quit, which might explain the higher cigarette use among dual users.
“We advise dual users to, at the very least, treat e-cigarettes like other nicotine replacement pharmacotherapy and recognize the potential for increased nicotine exposure,” said lead author Julie Wang, MPH, PhD, former postdoctoral fellow at UCSF. “Exposure to other e-cigarette toxicants also can induce or exacerbate respiratory issues.”
Even e-cigarette use alone, compared to no product use, was associated with poorer general health, breathing difficulty, chest pain, palpitations, coronary artery disease, arrhythmia, chronic obstructive pulmonary disease and asthma.
The PLOS ONE study is the latest of several UCSF studies on the harms of e-cigarettes, including their use exposing teens to toxic chemicals, doubling the risk of heart attack, making nonsmoking adolescents more likely to start smoking conventional cigarettes and expanding tobacco product use among youth.